7. Project Summary Since the inception of the WTC MMTP, health reports have focused on disorders of the aerodigestive tract and mental health consequences, and with the exception of spirometry, comparisons with general and normative population data have not been made. Furthermore, none of the previous studies comprehensively evaluated the changes of socioeconomic status in WTC responders after 9/11. Lowered SES is an important potential consequence of WTC exposures that can negatively impact the physical and mental health status among WTC responders. The main objective of the proposed study is to establish an expanded occupational health surveillance system that summarizes overall health status of WTC responders over time, and also provides information about symptoms not previously reported. Through this work, it is possible that other health outcomes will be identified and reported, such as autoimmune disorders. This expanded surveillance system will supplement reports the Data Center (DC) will be providing. To provide a reference population, the WTC cohort will be compared to the National Center for Health Statistics (NCHS) and the Behavioral Risk Factor Surveillance System (BRFSS) to compare physical and mental health status by matching variables. The comparison will estimate the magnitude of the impact of WTC exposure on the health of WTC responders compared with the general population in U.S. and New York-White Plains-Wayne, NY/NJ metropolitan area. Findings from this expanded surveillance will be reported through an integrated occupational health surveillance report. The term integrated occupational health surveillance report means a detailed and overall description of health status over time, with a comparison of groups both within the cohort and from the general population. The findings from this report will also aid in the future development of new guidelines for the implementation of an occupational health surveillance system for disasters, which is essential for disaster preparedness. Along with implementing a surveillance system, an additional objective will be to investigate ambi-directional effect modification between SES and health status. By ascertaining effect modification, SES will be added as one of the important variables necessary to perform surveillance. The study hypotheses for the effect modification investigation are 1) WTC exposures lower health status; 2) WTC exposures lower socioeconomic status; and 3) an interaction effect exists between these variables. This investigation for effect modification between health and SES is a unique research topic that has not been studied for WTC responders. Understanding the nature of the linkage between health and SES will help to identify high risk groups and offer a primary target for prevention and intervention strategies. With successful completion of this 2-year study, we expect a substantial improvement of the occupational health surveillance system for WTC responders.